Weight gain following smoking cessation has been associated with increased risk of relapse to smoking as well as development of diabetes. To date, there are no clinical treatments that target weight gain caused by smoking cessation. This project proposes to test efficacy of intranasal insulin treatment in controlling behavioral and metabolic aspects of food intake. Thus far, intranasal insulin treatment has demonstrated an exceptional safety profile, and preliminary data indicate that it has benefits on weight-related parameters. Intranasal administration delivers insulin directly to the Central Nervous System, without a significant peripheral absorption that would cause hypoglycemic events. Intranasal insulin reduces snacking as well as circulating free fatty acids - metabolites that significantly contribute to the development of diabetes. This is a Phase II, human experimental study with a specific objective to provide efficacy data for a larger Phase III trial of intranasal insulin treatment during smoking cessation. Subjects in this study will participate in two sessions in which they will receive intranasal insulin and placebo. After eating breakfast, their circulating free fatty acids will be assessed. We hypothesize lower free fatty acids in the intranasal insulin vs. placebo condition. Two and a half hours after lunch, subjects will participate in a mock taste test. They will be told that the objective is to rate palatability of three different kinds of cookes. Following the ratings, subjects will be told that the remainder of cookies will be discarded and that they are free to eat however much they would like. We hypothesize that the cookie consumption in the treatment (intranasal insulin) condition will be lower in comparison to the placebo condition. Milestones for this project include demonstrating intranasal insulin's benefit on satiety and metabolic profile during nicotine withdrawal.